Where did the ducks come from? Is it possible that you got a bantam mixed into your order?
I suspect that if she looks and acts healthy that maybe you are worrying too much. Make sure she isn't pushed away from the feeder by the larger ducks.
Some times they just grow different. Somewhere in my flock I have a duck whose legs and feet grew huge and his body stayed small. I planned to cull him, except for now I can't tell which duck it is because he grew up just fine. He sure did look odd for the longest time.
I suspect that if she looks and acts healthy that maybe you are worrying too much. Make sure she isn't pushed away from the feeder by the larger ducks.
Some times they just grow different. Somewhere in my flock I have a duck whose legs and feet grew huge and his body stayed small. I planned to cull him, except for now I can't tell which duck it is because he grew up just fine. He sure did look odd for the longest time.